CN111702170A

CN111702170A - Method for manufacturing three-dimensional shaped object

Info

Publication number: CN111702170A
Application number: CN201911153228.3A
Authority: CN
Inventors: 天谷浩一; 富田诚一
Original assignee: Matsuura Machinery Corp
Current assignee: Matsuura Machinery Corp
Priority date: 2019-03-01
Filing date: 2019-11-22
Publication date: 2020-09-25
Anticipated expiration: 2039-11-22
Also published as: CA3066272C; JP2020138502A; CN111702170B; CA3066272A1; JP6541206B1; US10946582B2; KR102074160B1; EP3702068B1; EP3702068A1; US20200276754A1

Abstract

The invention provides a method for manufacturing a three-dimensional shaped object, which can perform fume suction without inhibiting the irradiation of laser beams or electron beams, and can realize the problem by scattering powder by a scraper and irradiating laser beams or electron beams on a powder layer (3). The method for manufacturing a three-dimensional shaped object comprises the steps of arranging a suction unit (4) for sucking smoke generated from a powder layer (3) in a state of surrounding the whole periphery of a shaping table (1), and operating the suction unit (4) in the whole irradiation time, or selecting a suction reference position (42) which is currently closest to a moving irradiation reference position P and operating the suction reference position in a predetermined time span, or selecting a suction reference position (42) which is located in the direction opposite to the moving direction of the irradiation reference position P and operating the suction reference position in a predetermined time span, thereby solving the problem.

Description

Method for manufacturing three-dimensional shaped object

Technical Field

The present invention is directed to a method for manufacturing a three-dimensional shaped object on the premise of providing a suction unit that sucks a smoke generated by irradiating a laser beam or an electron beam onto a powder layer formed by the operation of a doctor blade over the entire periphery of a shaping table at the time of three-dimensional shaping.

Background

In the three-dimensional modeling in which the powder layer is irradiated with a laser beam or an electron beam, an aerosolized smoke is inevitably generated by the irradiation.

In the conventional art, the suction unit is communicated with the fume collector, and is disposed in a single state along a linear specific direction in an outer region of a modeling table on which a three-dimensional object is placed, with reference to a horizontal direction at an upper position of the modeling table.

In patent document 1, the discharge port V1 disposed in the wall portion of the chamber 1A located above and outside the modeling table 4 corresponds to a suction portion for sucking the flue gas in the chamber 1A by the fan 3B, and the wall portion is disposed linearly in a direction perpendicular to the paper surface of fig. 1 and communicates with the flue gas collector 3A (paragraph [0023], fig. 2, and fig. 3).

In patent document 2, the flue gas generated by laser beam irradiation and sintering is sucked from a suction port 72b provided in the support 43 communicating with the flue gas collector 19, discharged from a cover unit discharge port 72a, and communicated to the flue gas collector 19 via a wind box 21 (paragraphs [0061], [0063], fig. 1, and fig. 15).

The suction ports 72b are also arranged linearly in a direction perpendicular to the paper surface of fig. 1.

As in the above-described conventional arts, when the suction unit is disposed in a specific linear direction in the upper and outer region of the molding table with respect to the horizontal direction on the upper side of the molding table, the direction in which the fumes are sucked is also specified in a direction substantially orthogonal to the linear direction, and the distance between the irradiation position to the powder layer and the suction unit inevitably varies (fluctuates) as the irradiation position moves.

When the irradiation position and the suction portion are located on the opposite side with respect to the center position of the modeling table, the distance between them is large, and the suction speed of the smoke decreases.

In this case, when the laser beam or the electron beam is moved to the other irradiation position after the smoke has been generated, the laser beam or the electron beam has to transmit the smoke since the smoke is moved floating on the upper side of the other irradiation position.

The smoke gas that has passed through such floating can become a cause of preventing irradiation of each subsequent powder layer.

Further, the degree of obstruction of the irradiation by the amount of smoke passing therethrough is affected, and the irradiation is inevitably deviated.

Due to such drawbacks, sintering in the three-dimensional shaped object may vary to some extent, and this variation may cause a reduction in quality of the three-dimensional shaped object.

Prior art documents

Patent document 1: japanese patent laid-open publication No. 2018-72926

Patent document 2: japanese patent laid-open publication No. 2017-206744

Disclosure of Invention

The invention provides a method for manufacturing a three-dimensional shaped object, which arranges a smoke suction unit and executes a work instruction for suction so as not to prevent transmission and irradiation of a laser beam or an electron beam by smoke floating on the upper side of a powder layer.

In order to solve the above problems, the basic technical configuration of the present invention includes:

(1) a method for manufacturing a three-dimensional shaped object, comprising a step of forming a shaping area by spreading powder by a doctor blade on a shaping table disposed in a chamber and irradiating laser beams or electron beams onto powder layers formed by the spreading, wherein a suction unit for sucking smoke gas, which communicates with a collector for collecting smoke gas generated from the powder layers by the irradiation, is disposed above the shaping table at a position surrounding the entire periphery of the shaping table with reference to a horizontal direction, the suction areas capable of independently performing suction operation by the suction unit are disposed at equal intervals, a suction reference position as a center position of each suction area is determined, a common operation time span of each suction area is set, and a plurality of stationary irradiation reference positions are set based on positions regularly arranged at equal intervals in a two-dimensional direction in each powder layer, or setting a plurality of irradiation reference positions in a moving state in units of the movement time from an irradiation start position based on the movement time obtained from the common time span of the respective suction reference positions among the irradiation positions moving within the respective powder layers, determining an irradiation reference position P which is being irradiated at the plurality of stationary irradiation reference positions or the plurality of irradiation reference positions in the moving state, selecting a suction reference position having the shortest distance from the irradiation reference position P, and executing a work instruction of suction on a suction area corresponding to the suction reference position.

(2) A method for manufacturing a three-dimensional shaped object, comprising a step of forming a shaping area by spreading powder by a doctor blade on a shaping table disposed in a chamber and irradiating laser beams or electron beams onto powder layers formed by the spreading, wherein a suction unit for sucking smoke gas, which communicates with a collector for collecting smoke gas generated from the powder layers by the irradiation, is disposed above the shaping table at a position surrounding the entire periphery of the shaping table with reference to a horizontal direction, the suction areas capable of independently performing suction operation by the suction unit are disposed at equal intervals, a suction reference position as a center position of each suction area is determined, a common operation time span of each suction area is set, and a plurality of stationary irradiation reference positions are set based on positions of the powder layers regularly arranged at equal intervals in a two-dimensional direction, determining irradiation reference positions P which are irradiated at the plurality of stationary irradiation reference positions, setting adjacent irradiation reference positions P ' calculated from the time of the time span based on the moving direction and moving speed of the irradiation position of the irradiation reference position P, or setting a plurality of irradiation reference positions in a moving state in units of the moving time based on the moving time obtained from the time span from the irradiation start position among the irradiation positions moving in the respective powder layers, determining the irradiation reference position P which is irradiated at the plurality of irradiation reference positions in the moving state, setting the irradiation reference position P and the adjacent irradiation reference position P ' which is predetermined to move after the lapse of the time obtained from the time span from the irradiation reference position P, with reference to a straight line which is orthogonal to a straight line connecting the irradiation reference positions P and P ' at the irradiation reference position P, and executing a suction work instruction for the suction area corresponding to each suction reference position located at a position opposite to the irradiation reference position P 'adjacent to the irradiation reference position P'.

In the basic technical configuration (1), the suction of the flue gas can be achieved at a speed significantly higher than the moving speed of the irradiation position by the suction in the region surrounded by the position of the suction section having the shortest distance from the center position of the irradiation reference position of the flue gas, and the obstruction of the irradiation of the laser beam or the electron beam by the floating flue gas is sufficiently prevented.

In the basic technical constitution (2), the smoke is sucked in the direction opposite to the moving direction of the irradiation position of the laser beam or the electron beam, and the floating of the smoke can be completely prevented from interfering with the irradiation of the laser beam or the electron beam.

Drawings

FIG. 1 shows a plan view of example 1. The dashed line inside the suction unit indicates the presence of a gap on the molding table side where suction is achieved.

FIG. 2 is a plan view showing example 2. The broken line inside the suction portion is the same as that in fig. 1.

Fig. 3 is a diagram for explaining the arrangement state of the suction unit in the basic technical configurations (1) and (2), (a) is a side view, and (b) is a plan view. The broken line inside the suction portion is the same as that in fig. 1.

Fig. 4 is a plan sectional view for explaining the setting of the irradiation reference positions in the basic technical configuration (1), (a) shows a case where a plurality of irradiation reference positions are set based on positions regularly arranged at equal intervals in the two-dimensional direction in each powder layer, and (b) shows a case where a plurality of irradiation reference positions are set in units of the movement time from the irradiation start position with reference to the movement time obtained from the common time span of the respective suction reference positions in the irradiation positions moving in the powder layer. The gaps between the solid lines inside the suction unit indicate the presence of suction holes corresponding to the respective suction areas. In addition, P represents an irradiation reference position at which irradiation is being performed.

Fig. 5(a) is a flowchart for explaining the control process of the basic technical configuration (1) and shows the entire control process.

Fig. 5(b) is a flowchart for explaining the control process of the basic technical configuration (1) and shows a suction reference position for selecting a work instruction required to perform suction.

Fig. 5(c) is a flowchart for explaining the control process of the basic technical configuration (1) and showing a suction reference position for selecting a work instruction required to perform suction.

Fig. 6 is a plan view showing the arrangement of the respective suction areas and the respective suction reference positions on the premise of the flowchart of fig. 5(c) in the basic technical configuration (1).

Fig. 7 is a plan sectional view for explaining the setting of the irradiation reference positions in the basic technical configuration (2), (a) shows a case where a plurality of irradiation reference positions are set based on positions regularly arranged at equal intervals in the two-dimensional direction in each powder layer, and (b) shows a case where a plurality of irradiation reference positions are set in units of the movement time from the irradiation start position with reference to the movement time obtained from the common time span of the respective suction reference positions in the irradiation positions moving in the powder layer. The gaps between the solid lines inside the suction unit indicate the presence of suction holes corresponding to the respective suction areas. In addition, P represents an irradiation reference position at which irradiation is being performed, and P' represents an adjacent irradiation reference position.

Fig. 8(a) is a flowchart for explaining the control process of the basic technical configuration (2) and shows the entire control process.

Fig. 8(b) is a flowchart for explaining the control process of the basic technical configuration (2) and shows a suction reference position for selecting a work instruction for which suction is to be performed.

Fig. 8(c) is a flowchart for explaining the control process of the basic technical configuration (2) and shows a suction reference position for selecting a work instruction for which suction is to be performed.

Fig. 9 shows an embodiment of the basic technical configurations (1) and (2) in which the respective on-off valves corresponding to the respective suction areas are disposed in a continuous state without being distinguished from each other, and are disposed in an adjacent state, wherein (a) is a plan view and (b) is a side view. The vertical arrows in (b) indicate the moving direction of the on-off valve. The horizontal dotted line in (a) and the vertical dotted line in (b) indicate the boundary line of the suction region in which the suction operation can be performed independently.

Fig. 10 shows an embodiment of the basic technical configurations (1) and (2) in which the respective switching valves corresponding to the respective suction areas are provided adjacent to each other in a state where the divided suction areas are adjacent to each other, (a) is a plan view of a case where the switching valve is provided at an inlet of the suction area, (b) is a plan view of the switching valve provided at a middle portion of each pipe communicating the respective suction areas with the flue gas collector, and (c) is a plan view of the switching valve provided at an end portion on the flue gas collector side of the pipe communicating the suction areas with the flue gas collector.

Fig. 11 shows an embodiment of basic technical configurations (1) and (2) in which suction fans and suction switches connected to the suction fans are provided in respective divided suction areas, where (a) is a plan view and (b) is a side sectional view.

Description of the reference numerals

1 moulding table

2 walls of the chamber

3 powder layers to be irradiated

31 irradiation reference position

4 suction part

41 suction area

42 suction reference position

43 suction hole

5 tube

6 flue gas collector

7 switch valve

8 suction fan

9 suction switch

Detailed Description

In the basic technical configurations (1) and (2) requiring the step of scattering the powder on the molding table 1 and irradiating the powder layers 3 formed by the scattering with the laser beam or the electron beam, as shown in fig. 3(a) and (b), the suction portion 4 communicating with the flue gas collector 6 is disposed above the molding table 1 in a state of surrounding the molding table 1 with reference to the horizontal direction, and is significantly different from the configuration in which the suction portion is linearly disposed in a specific direction as in the conventional art.

However, if the suction section 4 surrounding the modeling table 1 is provided and only 1 flue gas collector 6 is provided as in the prior art, the distance from the suction section 4 to the pipe 5 of the flue gas collector 6 becomes long, and therefore, a plurality of flue gas collectors 6 can be provided, specifically, for example, in the case where the modeling table 1 is rectangular, 4 flue gas collectors 6 can be provided as shown in fig. 3 (a).

In fig. 3(a) and (b), the laser beam or electron beam irradiation source and the mirrors for the respective beams are not shown.

Fig. 3(a) and (b) show an embodiment in which the suction portion 4 is provided in the chamber, but it is needless to say that, as in patent document 1, an embodiment in which the suction portion 4 is provided in the wall portion 2 of the chamber can be selected as the basic technical configuration (1) and (2).

The basic technical configurations (1) and (2) include a step of forming a sintered layer of a three-dimensional shaped object by the irradiation and then cutting the surface of the sintered layer and the vicinity thereof, but the cutting step is not always necessary.

However, the cutting step is required to ensure the correct shape of the three-dimensional object.

In the basic technical configurations (1) and (2), the position where the pumping operation is performed is selected and changed in accordance with the change in the irradiation position in the sintered layer.

Therefore, in the basic technical configurations (1) and (2), the suction areas 41 capable of independently performing the suction operation are set at equal intervals in the suction unit 4, and the suction reference position 42 is set at the center position of each suction area 41, based on which the operation position of the suction unit 4 corresponding to the change in the irradiation position can be quickly selected based on such suction reference position 42.

In order to allow each suction area 41 to independently perform a suction function, each suction area 41 needs to communicate with the flue gas collector 6 through a specific pipe 5 as shown in fig. 4(a) and 7(a), or needs to function as a specific on-off valve 7 corresponding to each suction area 41 as described later.

In fig. 4(a), (b) and fig. 7(a), (b), the suction holes 43 are used for the suction operation independently for each suction area 41, but the suction holes 43 are not essential, and a gap for realizing suction may be provided on the modeling table 1 side of each suction area 41.

The operation time of each suction region 41 is influenced by the degree of change in the irradiation position, but a predetermined time span is set for the operation time for easy control.

Such a time span varies depending on the size and shape of the three-dimensional object, but it usually takes 10 seconds to 1 minute.

In the basic technical configuration (1), the smoke is sucked by the operation of 1 suction region 41, and in the basic technical configuration (2), there may be only 1 suction region 41 located in the direction opposite to the moving direction of the irradiation position.

In view of such a single work, in the case where smoke is generated at the center position of the modeling table 1, if the suction force in units of the respective suction areas 41 is such a degree that the smoke can be sucked individually, the above-described effects of the basic technical constitutions (1) and (2) can be achieved individually.

This is because, in the basic technical configurations (1) and (2), the irradiation position of each powder layer 3 that is the farthest from each suction region 41 is the center position of the modeling table 1, and when the irradiation position that is being irradiated in each suction region 41 is away from the center position, significantly stronger suction can be exerted than when the irradiation is performed at the center position.

In the basic technical configurations (1) and (2), the plurality of irradiation reference positions 31 are set by a below a shown in fig. 4(a) and 7(a) or B shown in fig. 4(B) and 7 (B).

A sets a plurality of stationary irradiation reference positions 31 based on positions regularly arranged at equal intervals in the two-dimensional direction in each powder layer 3.

B sets a plurality of irradiation reference positions 31 in a moving state in units of a moving time based on the moving time obtained from the time span set for each suction region 41 from the movement start position among the irradiation positions moving within each powder layer 3.

In the above-mentioned a, a plurality of stationary irradiation reference positions 31 are set, based on the fact that in the sintering region where the respective powder layers 3 are irradiated with the laser beam or the electron beam, the stationary irradiation reference positions 31 are all necessarily the objects to be irradiated.

Therefore, in order to detect the irradiation reference position P being irradiated from among the plurality of stationary irradiation reference positions 31 of a, it is necessary to determine to which irradiation reference position 31 of the plurality of irradiation reference positions 31 the laser beam or the electron beam has moved at any time during the entire irradiation time, and the irradiation reference position P can be specified by this determination.

The laser beam or electron beam is not moved at regular times in the plurality of arrangement positions of a.

However, the irradiation reference position P determined by the above determination corresponds to any of the plurality of stationary irradiation reference positions 31 arranged regularly.

The plurality of irradiation reference positions 31 in the moving state of B are not arranged at equal intervals as in the case of a.

Therefore, it is necessary to determine at which position of each powder layer 3 the irradiation reference position P obtained from the time unit is present, among the plurality of irradiation reference positions 31 in the moving state of B.

If it is considered that the irradiation positions are uniformly moved in sequence in the sintering area of each powder layer 3, the irradiation reference positions 31 may be set substantially uniformly in each powder layer 3 according to a regular time from the movement start timing in units of time derived from the suction time span of the suction.

In the basic technical configuration (2), in order to specify not only the irradiation reference position P being irradiated but also the moving direction of the laser beam or electron beam at the irradiation reference position P, the adjacent irradiation reference positions P' are set by the following positions α shown in fig. 7(a) or the following positions β shown in fig. 7 (b).

α is a position calculated from the time of the time unit of B based on the moving direction and moving speed of the irradiation position of the irradiation reference position P set by a.

β is a position to be moved by a time unit of B from the irradiation reference position P set by B.

In the case where the irradiation position of the laser beam or the electron beam is moved at the irradiation reference position P set in a, the moving direction and the moving speed are necessarily determined.

In α, the adjacent irradiation reference positions P 'are set in the time unit of B in accordance with the moving direction and the moving speed, but the actual irradiation position does not always pass through and move at the adjacent irradiation reference positions P' set above, considering that the actual irradiation position changes sequentially.

However, the irradiation reference position P' adjacent to each other calculated from α can clearly reflect and specify the moving direction of the irradiation position of the irradiation reference position P.

The irradiation reference position P actually irradiated and the adjacent irradiation reference position P' set in β are actually moved in a predetermined time unit of B from the irradiation position actually moved, and it is needless to say that the moving direction of the irradiation reference position P is determined.

In the basic technical configuration (1) based on the plan sectional views of fig. 4(a) and (b), in order to select the suction reference position 42 having the shortest distance from the center position of the irradiation reference position 31 to be irradiated and execute an operation command for the suction unit 4 surrounding the suction reference position 42, the following steps are employed, as shown in the flowchart of fig. 5(a), to set the shape of the three-dimensional shaped object by the CAD/CAM system and to set the number N of the powder layers 3 stacked by the doctor blade.

Step 1 is to set a plurality of stationary irradiation reference positions 31 of the above-mentioned a or a plurality of irradiation reference positions 31 of the above-mentioned B in a moving state.

And a step 2 of determining an irradiation reference position P to be irradiated from among the plurality of irradiation reference positions 31 set in the step 1.

In step 3, the suction reference position 42 having the shortest distance from the irradiation reference position P is selected.

And a step 4 of executing a suction operation command for the suction area 41 corresponding to the suction reference position 42 selected in the step 2.

In reality, the selection of the suction reference position 42 having the shortest distance from the center position can be realized by the following embodiment of the process as shown in the flowchart of fig. 5 (b).

In step 1, the distance between the irradiation reference position P of the polar coordinates (r, θ) with the center position of the modeling table as the origin and all the suction reference positions 42 is calculated.

In step 2, as shown in fig. 4(a) and (b), the suction reference position S arbitrarily selected as the start position is compared with the distance calculated in step 1 between the uncompared suction reference positions 42 existing in the clockwise direction in which θ decreases as shown in fig. 4(a) or the counterclockwise direction in which θ increases as shown in fig. 4 (b).

In the comparison of step 2, the suction reference position 42 having a smaller distance is selected when one of the two suction reference positions 42 is smaller than the other, and any one of the suction reference positions 42 is selected when the two suction reference positions 42 are equidistant.

And a step 4 of repeating the comparison in the step 2 and the selection in the step 3 until the comparison in the step 2 and the selection in the step 3 are completed between the suction reference position 42 determined in the step 2 and the adjacent suction reference positions S' shown in fig. 4(a) and (b) in the counterclockwise direction or the clockwise direction.

In the irradiation reference position P during irradiation, if it is considered that a predetermined region width exists, the irradiation reference position P in step 1 is referred to as "the center position of the irradiation reference position P" when the irradiated sintered region is used as a reference.

However, in the computer involved in the control of the three-dimensional modeling, the center position of the irradiation reference position P is inevitably recorded and is the subject of the control, and the irradiation reference position P in the basic technical configuration (1) is inevitably the "center position of the irradiation reference position P", which coincides with the technical gist in the case of using the irradiated sintered region as a reference.

In the above step 3, when the distance between the two suction reference positions 42 is equal, one of the suction reference positions 42 is selected, and the selection of one does not affect the subsequent steps.

The magnitude relationship of the distance from the irradiation reference position P being moved is sequentially compared clockwise or counterclockwise from the selected specific suction reference position 42, and the selection of the suction reference position 42 can be smoothly realized by using the polar coordinates (r, θ).

On the other hand, in the rectangular coordinates (X, Y), a complicated operation of specifying the coordinate positions (X ', Y') adjacent to the specified coordinate positions (X, Y) and determining whether the coordinate positions (X, Y) and (X ', Y') are positioned in the clockwise direction or the counterclockwise direction is required, and the clockwise direction or the counterclockwise direction cannot be generally specified like the polar coordinates (r, θ).

In the above-described embodiment based on such sequential correspondence, the shortest distance to the irradiation reference position P can be calculated regardless of the arrangement state of each suction region 41 and each suction reference position 42 corresponding to the suction region 41.

As shown in fig. 4, since the general modeling table 1 has a rectangular planar shape in the horizontal direction, the suction units 4 are also arranged along the sides of the rectangle.

In this case, as shown in the graph of the rectangular coordinates (x, y) in fig. 6 and the flowchart in fig. 5(c), the suction reference position 42 having the shortest distance from the center position can be selected by the following procedure.

In step 1, an x-axis and a y-axis parallel to the sides of a rectangle are selected from rectangular coordinates (x, y) with the center position of a modeling table as the origin, and coordinates (a, b) of an irradiation reference position P to which irradiation is being performed are determined.

In step 2, coordinates (a, B), (-a, B), (a, B), and (a, -B) at 4 points where a straight line parallel to the x-axis direction and the y-axis direction intersects the inlet of the suction unit 4 are set with respect to the coordinates (a, B).

And 3, selecting the minimum distance from the distances A-a, A + a, B-B and B + B between the position of the coordinates (a and B) and the coordinates at the 4 positions.

And a step 4 of selecting a suction reference position having the smallest distance with respect to the coordinate position selected in the step 3.

In step 3, the selection of the coordinate of the minimum value among the 4 distances may be performed by comparing the coordinates (4 × 3 × 2 × 1)/(2 × 2) 6 times, and it is not necessary to set the polar coordinates (r, θ) as in the embodiment of fig. 5 (b).

However, the 4 coordinate positions may be set with polar coordinates (r, θ) and the distances to the suction reference positions 42 may be sequentially compared in the same manner as in the flowchart of fig. 5(b), and in this case, the number of comparisons is only 4, so that rapid comparison can be achieved.

Therefore, in step 1, the technical configuration using the polar coordinates (r, θ) instead of the rectangular coordinates (x, y) is technically equivalent to the technical configuration of the flowchart of fig. 5(c), and the embodiment of fig. 5(c) includes the embodiment using the polar coordinates (r, θ) as a technical range.

In the case of using rectangular coordinates (X, Y) as in fig. 6, it is determined whether or not the sides of the rectangle in which the coordinates selected in the step 3 exist are along the X-axis direction or the Y-axis direction, and in the case of the sides along the X-axis direction, it is necessary to sequentially compare the magnitude relationship of the absolute value of X '-a, which is the difference between the X-coordinate value X' of each suction reference position 42 and the coordinate value a, and in the case of the sides along the Y-axis direction in the step 3, it is necessary to sequentially compare the absolute value of Y '-b, which is the difference between the Y-axis value Y' of the suction reference position 42 of the side and the coordinate value b, and the case of polar coordinates (r, θ) based on the same comparison as the flowchart of fig. 5(b) is slightly more complicated.

Such a situation in rectangular coordinates (x, y) objectively supports the above-described technically equivalent relationship.

In the basic technical configuration (1), in a special case, there are a plurality of suction reference positions 42 that are the shortest distance from the center position of the modeling table 1.

Specifically, for example, when the modeling table 1 is rectangular, 2 suction reference positions 42 are formed, the distance from which to the center position is the shortest, when the modeling table 1 is square, as described later in example 1, and when the end of the modeling table 1 is equidistant from the inlet of the

suction unit

4, 4 suction reference positions 42 are formed, the distance from which to the center position of the modeling table 1 is the shortest, and when the modeling table 1 is circular, as described later in example 2, and when the inlet of the suction unit 4 is formed concentrically with the circle, all the suction reference positions 42 are the shortest distance from the center position.

However, in the case where the irradiation reference position 31 actually moves in the center position of the modeling table 1 for a short time and there are a plurality of suction reference positions 42 having the shortest distance, the amount of smoke in each direction is reduced in consideration of suction in a plurality of directions, as compared with the case where suction is performed in one direction, and the effect of sufficiently preventing the laser beam or the electron beam from being obstructed by the drift of smoke is ensured without changing.

In the basic technical configuration (2) based on the plan views of fig. 7(a) and (b), as shown in the flowchart of fig. 8(a), the shape of the three-dimensional shaped object is set by the CAD/CAM system, and the number N of the powder layers 3 stacked by the doctor blade is set, and the following steps are employed.

Step 1 is to set a plurality of stationary irradiation reference positions 31 of the above-mentioned a or a plurality of irradiation reference positions 31 in a moving state of the above-mentioned B.

And a step 3 of setting adjacent irradiation reference positions P' by the above-mentioned alpha or beta.

Step 4 is to set a linear equation in which the irradiation reference positions P and P' obtained in

steps

2 and 3 are connected to each other, the linear equation being orthogonal to the irradiation reference positions P.

And a step 5 of executing a suction operation command for the suction region 41 corresponding to the suction reference position 42 existing in the region opposite to the adjacent irradiation reference position P' set in the step 3 with reference to the 4 orthogonal straight lines.

The specific selection of the suction reference position 42 existing on the opposite side of the irradiation reference position P' adjacent thereto can be realized by the following steps as shown in the flowchart of fig. 8 (b).

In step 1, in polar coordinates (r, θ) with the center position of the modeling table as the origin, the orthogonal straight line equation rcos θ/a + rsin θ/b is set to 1.

Where "a" and "b" are R obtained from angles of 0 and pi/2, respectively, and when the coordinates of the irradiation reference position P being irradiated are (R, α) and the coordinates of the adjacent irradiation reference position P ' are (R ', α '),

a＝{R·R’cos(α-α’)-R²}/(R’cosα’-Rcosα)，

b＝{R·R’sin(α-α’)-R²}/(R’sinα’-Rsinα)。

step 2, the magnitude relation between 1 and R ' cos α '/a + R ' sin α '/b of the adjacent irradiation reference positions P ' (R ', α ') is determined.

In the working procedure 3, the first step of the method,

(1) in step 2, when R 'cos α'/a + R 'sin α'/b > 1, the suction reference position 42 satisfying R "cos α"/a + R "sin α"/b ≦ 1 is selected for the coordinates (R ", α) of each suction reference position 42.

(2) In step 2, when R 'cos α'/a + R 'sin α'/b < 1, all the suction reference positions 42 satisfying that R "cos α"/a + R "sin α"/b is not less than 1 are selected for the coordinates (R ", α) of each suction reference position 42.

All the suction reference positions 42 selected in the steps 3(1) and 2 are located on the opposite side of the irradiation reference position P ' adjacent to the orthogonal straight line set in the step 1 with reference to the orthogonal straight line, and are immediately apparent from elementary mathematics such as the magnitude relationship between the equation R ' cos α '/a + R ' sin α '/b of the orthogonal straight line and 1.

To explain the derivation of the general formulae of a and b, R { R 'sin (θ - α') -Rsin (θ - α) } ═ R · R 'sin (α - α') holds in a straight line connecting the irradiation reference position P (R, α) being irradiated and the irradiation reference position P '(R', α ') being adjacent to the irradiation reference position P' (R ', α').

Therefore, with respect to a straight line equation orthogonal to the straight line equation and passing through the irradiation reference position P (R, α), R { R 'cos (θ - α') -Rcos (θ - α) } ═ R · R 'cos (α - α') -R } can be derived²。

The above equation can be modified to R { (R ' cos α ' -Rcos α) cos θ + (R ' sin α ' -Rsin α) sin θ }/{ R · R ' cos (α - α ') -R { (R ' sin α ' -Rcos α) } sin θ + (R ' sin α -sin α)²1, so with a, b, one can derive

a＝{R·R’cos(α-α’)-R²}/(R’cosα’-Rcosα)，

b＝{R·R’sin(α-α’)-R²}/(R’sinα’-Rsinα)。

Although the flowchart of fig. 8(b) has been described based on the polar coordinates (r, θ), it may be set to x/a + y/b equal to 1 by using rectangular coordinates (x, y) and setting the coordinates passing through the x-axis and the y-axis to (a, 0) and (0, b) for the orthogonal straight line passing through the irradiation reference position P, as shown in fig. 7(a) and (b).

Under the above setting, the magnitude relationship between X '/a + Y'/b and 1 of the irradiation reference positions P '(X', Y ') adjacent to each other is determined, and all the suction reference positions 42 having the magnitude relationship opposite to that in the case of P' (X ', Y') can be selected with respect to the coordinates (X ", Y") of each suction reference position 42 and the magnitude relationship between X '/a + Y'/b and 1.

That is, the embodiment shown in the flowchart of fig. 8(b) is technically equivalent to the above-described method of performing calculation using rectangular coordinates, and such an embodiment of the calculation method is included as a technical scope of course.

In the case of selecting all the pumping reference positions 42 in which an opposite inequality to the inequalities of the adjacent irradiation reference positions P ' (X ', Y ') is established, efficient determination and selection can be achieved by sequentially changing θ ″ when polar coordinates (r, θ) are used, whereas in the case of using rectangular coordinates (X, Y), it is necessary to individually change the numerical values of X "and Y" with respect to the coordinates (X ", Y) of each pumping reference position 42 to sequentially determine whether the opposite inequalities are established, and in consideration of these, there is a little inconvenience in selecting the efficient pumping reference positions 42 when rectangular coordinates (X, Y) are used.

However, such inconvenience is predictable to those skilled in the art, and thus cannot be regarded as a negative basis for the equivalence of the above-described techniques.

The embodiment shown in the flowchart of fig. 8(b) is characterized in that each of the suction reference positions 42 is individually determined whether or not it is located in the direction opposite to the direction of the adjacent irradiation reference position 31, and the configuration is simple.

As another embodiment of selecting the suction reference position 42 on the opposite side of the adjacent irradiation reference position P', as shown in the flowchart of fig. 8(c), the following procedure can be performed.

In step 1, in the polar coordinates (r, θ) with the center position of the modeling table as the origin, as shown in fig. 7(a) and (b), the equation rcos θ/a + rsin θ/b of the orthogonal straight line is set to 1.

a＝{R·R’cos(α-α’)-R²}/(R’cosα’-Rcosα)，

b＝{R·R’sin(α-α’)-R²}/(R’sinα’-Rsinα)。

step 2, as shown in FIGS. 7(a) and (b), a two-point intersection Q of the line between the linear equation and the inlet of the suction part is calculated₁(R₁’，α₁') and Q₂(R₂’，α₂’)。

Wherein Q is₁Is configured at Q₂The left side of,Upper or left upper position (Q is shown in FIGS. 7(a) and (b)₁Is arranged at Q₂Upper left side of).

Step 3, the magnitude relation between 1 and R ' cos α '/a + R ' sin α '/b of the adjacent irradiation reference positions P ' (R ', α ') is determined.

In the step (4), the first step is carried out,

(1) in the step 3, when R 'cos α'/a + R 'sin α'/b > 1, Q is selected in order₁Starting in the counterclockwise direction from the direction in which theta becomes larger up to Q₂The pumping reference position 42 existing in the range up to this point.

(2) In the step 3, when R 'cos α'/a + R 'sin α'/b < 1, Q is selected in order₁From a clockwise direction in which theta becomes smaller to Q₂The pumping reference position 42 existing in the range up to this point.

In the embodiment shown in the flowchart of FIG. 8(c), the signal level is determined from two intersections Q₁，Q₂When the suction reference position 42 is selected in the clockwise direction or the counterclockwise direction, since a very complicated calculation is required when rectangular coordinates (x, y) are used, the suction reference position 42 can be smoothly selected by setting polar coordinates (r, θ) with respect to each suction reference position 42, which is the same as the embodiment shown in fig. 4(b) of the basic technical configuration (1).

In the embodiment shown in the flowchart of FIG. 8(c), when R '. cos α'/a + R '. sin α'/b > 1, the slave intersection Q is selected₁Starting in the counter-clockwise direction up to Q₁The suction reference position 42 exists in the range up to this point on the basis that these counterclockwise and clockwise directions are opposite directions toward the adjacent irradiation reference position P ' satisfying R '. cos α '/a + R '. sin α '/b > 1 with reference to the orthogonal straight line.

Similarly, when R '. cos α'/a + R '. sin α'/b < 1, the slave intersection Q is selected₁Starting in the clockwise direction up to Q₁The suction reference position 42 existing in the range up to this point is based on these clockwise times with the orthogonal straight line as a referenceThe needle and the counterclockwise direction are the directions opposite to the directions toward the adjacent irradiation reference positions P ' satisfying R '. cos α '/a + R '. sin α '/b < 1.

The embodiment shown in the flowchart of FIG. 8(c) is characterized by the ability to pass through the two intersections Q₁、Q₂The clockwise or counterclockwise selection is made together with the suction reference position 42 located in the opposite direction to the irradiation reference position 31 set as the adjacent one.

In the embodiment shown in fig. 9(a) and (b), in the suction unit 4, the respective open/close valves 7 which are arranged in a continuous state without distinguishing the respective suction areas 41 and correspond to the respective suction areas 41 are provided in a state adjacent to the inlets of the respective suction areas 41, and the open/close valve 7 of the suction area 41 which performs the operation command of suction is opened.

In the above embodiment, by using each suction area 41 and the adjacent on-off valve 7 having a simple structure without distinction, it is possible to apply to the setting of the suction reference position 42 and the selection of the suction reference position 42 in the basic technical configurations (1) and (2).

In the embodiment shown in fig. 10, the switching valve 7 corresponding to each suction area 41 is disposed in a state of separating the suction areas 41 from each other in the suction unit 4, and the switching valve 7 at the suction reference position 42 for executing the operation command of suction is opened at the inlet of the suction area 41 or at the middle portion of each pipe 5 connecting the suction areas 41 to the flue gas collector 6 or at the end portion on the flue gas collector 6 side.

In the above-described embodiment, the setting of the suction reference position 42 and the selection of the suction reference position 42 in the basic technical configurations (1) and (2) can be applied by the respective suction regions 41 and the suction reference positions 42 corresponding to the suction regions 41 that have been distinguished, and the arrangement of the open-close valve 7.

Further, in the above embodiment, the setting position of the on-off valve 7 can be selected at 3 points, and as shown in fig. 10(b) and (c), when the on-off valve 7 is set in the pipe 5 communicating with the flue gas collector 6, it is possible to avoid arrangement of a device for operating the on-off valve 7 at or near the inlet of the suction unit 4, which makes it possible to realize safe operation.

In the embodiment shown in fig. 11, the suction unit 4 is provided with a suction fan 8 and a suction switch 9 connected to the suction fan 8, which are disposed in the respective suction areas 41 so as to separate the respective suction areas 41 from each other, and the suction switch 9 and the suction fan 8 in the suction area 41 for executing the operation command for suction are operated.

In the above-described embodiment, the suction reference position 42 is slightly more complicated in design than the embodiments shown in fig. 9 and 10, because the suction fan 8 having the separate suction switch 9 needs to be provided without using the on-off valve 7 as a unit of operation.

However, in the embodiment shown in fig. 11, the suction of the flue gas and the movement of the flue gas to the flue gas collector 6 can be realized by the suction fans 8 in the respective suction areas 41, and the space of the flue gas collector 6 can be reduced because there is no need to provide a large suction fan 8 in the flue gas collector 6.

The more the laser beam or electron beam is irradiated, the more the amount of smoke generated tends to increase.

In view of such circumstances, in the basic technical configurations (1) and (2), an embodiment may be adopted which is characterized in that the suction amount per unit area of the suction portion is set to be larger as the irradiation amount of the laser beam or the electron beam is larger.

In the above embodiment, even if the irradiation amount is increased and the amount of smoke generated is increased, the smoke can be rapidly sucked by increasing the degree of suction, and the smoke is appropriately prevented from obstructing the transmission and irradiation of the laser beam or the electron beam.

In either of the basic technical configurations (1) and (2), as shown in fig. 1 and 2, it is preferable to adopt an embodiment in which the end of the modeling table 1 is equidistant from the suction section 4 with respect to the horizontal direction.

This is because, by such equidistant setting, the deviation of the time for the smoke to move from the position irradiated with the laser beam or the electron beam to the suction section 4 is further reduced as compared with the design that is not equidistant.

Examples

The following description will be made based on examples.

Example 1

Example 1 is characterized in that, in the basic technical configurations (1) and (2), as shown in fig. 1, the planar shape of the modeling table 1 in the horizontal direction is a square, and the suction units 4 are arranged so as to form sides of the square (fig. 1 shows an embodiment in which the suction units 4 are divided as shown in fig. 10).

As described above, the modeling table 1 is generally square in the horizontal plane direction, and the suction units 4 are also arranged along the sides of the square according to the shape of the modeling table 1 in example 1.

In example 1, the embodiment in which the end of the modeling table 1 is equidistant from the suction unit 4 with respect to the horizontal direction can be easily applied.

Fig. 1 shows a state where the suction unit 4 is not provided at a portion parallel to the end of the modeling table 1, that is, in the vicinity of a corner, but it goes without saying that the suction unit 4 may be provided at the corner and the vicinity thereof.

Example 2

Example 2 in the basic technical configurations (1) and (2), as shown in fig. 2, the modeling table 1 is characterized in that the planar shape in the horizontal direction is a circle, and the suction units 4 are arranged concentrically with respect to the circle (fig. 2 shows an embodiment in which the suction units 4 are not divided but are in a continuous state as shown in fig. 9).

The modeling table 1 of fig. 2 uses less frequency than the square modeling table 1.

However, in example 2, when the end portion of the modeling table 1 and the suction portion 4 are set to be equidistant from each other in the horizontal direction by the concentric circular arrangement shown in fig. 2, the suction portion 4 can be set in the entire region surrounding the modeling table 1, and the space can be effectively used.

Industrial applicability

The present invention is contrived to prevent the smoke generated by irradiation of a laser beam or an electron beam from interfering with the transmission and subsequent irradiation of the respective beams, thereby reducing or preventing quality variation of a three-dimensional object, and can be widely used in the entire technical configuration of three-dimensional modeling.

Claims

1. A method for manufacturing a three-dimensional shaped object, comprising a shaping region forming step of scattering powder by a doctor blade on a shaping table disposed in a chamber and irradiating a powder layer formed by the scattering with a laser beam or an electron beam,

in the manufacturing method, a suction unit for sucking the smoke gas, which communicates with a collector for collecting the smoke gas generated from the powder layer by the irradiation, is provided above the molding table at a position surrounding the entire periphery of the molding table with reference to the horizontal direction, the suction areas capable of independently performing a suction operation by the suction unit are arranged at equal intervals, a suction reference position as a center position of each suction area is determined, a common operation time span of each suction area is set, a plurality of stationary irradiation reference positions are set based on positions regularly arranged at equal intervals in the two-dimensional direction in each powder layer, or a plurality of irradiation reference positions in a moving state are set in units of the movement time from an irradiation start position in each powder layer based on a movement time obtained from the common time span of each suction reference position in the irradiation position moving in each powder layer, and after the irradiation reference positions P which are irradiated on the plurality of stationary irradiation reference positions or the plurality of irradiation reference positions in the moving state are determined, selecting the suction reference position with the shortest distance from the irradiation reference positions P, and executing a suction work instruction on the suction area corresponding to the suction reference position.

2. The method of manufacturing a three-dimensional shaped object according to claim 1,

selecting a suction reference position having the shortest distance to an irradiation reference position P being irradiated,

step 1, calculating the distance between the irradiation reference position P of the polar coordinates (r, theta) with the central position of the modeling table as the origin and all the suction reference positions,

a step 2 of comparing a magnitude relation of the distance calculated in the step 1 with a magnitude relation of a suction reference position arbitrarily selected as a start position and a suction reference position existing in a clockwise direction in which θ becomes smaller or a counterclockwise direction in which θ becomes larger and not compared,

a step 3 of selecting a suction reference position having a smaller distance when one of the two suction reference positions is smaller than the other of the two suction reference positions in the comparison in the step 2, and selecting either one of the two suction reference positions when the two suction reference positions are equal in distance,

and a step 4 of repeating the comparison in the step 2 and the selection in the step 3 until the comparison in the step 2 and the selection in the step 3 are completed between the suction reference position determined in the step 2 and the suction reference position adjacent in the counterclockwise direction or the clockwise direction.

3. The method of manufacturing a three-dimensional shaped object according to claim 1,

the shape of the modeling table is a rectangle, and in a suction part set in a state of being parallel to the sides of the rectangle, a suction reference position having the shortest distance to the center position of the irradiation reference position P is selected by the following steps,

step 1, selecting x-axis and y-axis parallel to the sides of the rectangle from rectangular coordinates (x, y) with the center position of the modeling table as the origin, determining the coordinates (a, b) of an irradiation reference position P being irradiated,

step 2, setting coordinates (A, B), (-A, B), (a, B), (a, -B) at 4 points where a straight line parallel to the x-axis direction and the y-axis direction intersects the inlet of the suction part, with respect to the coordinates (a, B),

step 3, selecting the minimum distance from the distances A-a, A + a, B-B and B + B between the position of the coordinates (a, B) and the coordinates at the 4 positions,

4. A method for manufacturing a three-dimensional shaped object, comprising a shaping region forming step of scattering powder by a doctor blade on a shaping table disposed in a chamber and irradiating each powder layer formed by the scattering with a laser beam or an electron beam,

in the manufacturing method, a suction part for sucking smoke gas, which is communicated with a collector for collecting smoke gas generated from the powder layer by the irradiation, is arranged at a position which is arranged at the upper side of the modeling table and surrounds the whole periphery of the modeling table with a horizontal direction as a reference, each suction area capable of independently performing suction operation by the suction part is arranged at equal intervals, a suction reference position which is a central position of each suction area is determined, a common operation time span of each suction area is set, a plurality of static irradiation reference positions are set based on positions which are regularly arranged at equal intervals in a two-dimensional direction in each powder layer, an irradiation reference position P which is irradiated on the plurality of static irradiation reference positions is determined, then adjacent irradiation reference positions P' calculated according to the time of the time span are set based on the moving direction and the moving speed of the irradiation position of the irradiation reference position P, or a plurality of irradiation reference positions in a moving state are set in units of a moving time from an irradiation start position among the irradiation positions moving in the respective powder layers based on the moving time obtained from the time span, and after the irradiation reference position P in the moving state where irradiation is performed is determined, the irradiation reference position P and an adjacent irradiation reference position P ' to be moved in a predetermined manner from the irradiation reference position P over a time obtained from the time span are set, and a pumping command for pumping is executed for a pumping region corresponding to each pumping reference position located at a position opposite to the adjacent irradiation reference position P ' with reference to a straight line orthogonal to a straight line connecting the irradiation reference positions P and P ' at the irradiation reference position P.

5. The method of manufacturing a three-dimensional shaped object according to claim 4,

selecting each of the suction reference positions located on the opposite side of the irradiation reference position P 'adjacent to the irradiation reference position P' with reference to the orthogonal straight line,

step 1, in polar coordinates (r, theta) with the center position of the modeling table as the origin, setting the orthogonal straight line equation rcos theta/a + rsin theta/b as 1,

a＝{R·R’cos(α-α’)-R²}/(R’cosα’-Rcosα)，

b＝{R·R’sin(α-α’)-R²}/(R’sinα’-Rsinα)，

step 2 of determining the magnitude relation between R ' cos α '/a + R ' sin α '/b and 1 in the adjacent irradiation reference positions P ' (R ', α '),

in the working procedure 3, the first step of the method,

(1) in step 2, when R 'cos α'/a + R 'sin α'/b > 1, a suction reference position satisfying R "cos α"/a + R "sin α"/b.ltoreq.1 is selected for the coordinates (R ", α) of each suction reference position,

(2) in step 2, when R 'cos α'/a + R 'sin α'/b < 1, all the suction reference positions satisfying that R "cos α"/a + R "sin α"/b is not less than 1 are selected for the coordinates (R ", α) of each suction reference position.

6. The method of manufacturing a three-dimensional shaped object according to claim 4,

a＝{R·R’cos(α-α’)-R²}/(R’cosα’-Rcosα)，

b＝{R·R’sin(α-α’)-R²}/(R’sinα’-Rsinα)，

step 2 of calculating a two-point intersection Q of the line between the linear equation and the inlet of the suction unit₁(R₁’，α₁') and Q₂(R₂’，α₂’)，

Wherein Q is₁Is configured at Q₂The left side, the upper side or the left upper side,

step 3 of determining the magnitude relation between R ' cos α '/a + R ' sin α '/b and 1 in the adjacent irradiation reference positions P ' (R ', α '),

in the step (4), the first step is carried out,

(1) in the step 3, when R 'cos α'/a + R 'sin α'/b > 1, Q is selected in order₁Starting in the counterclockwise direction from the direction in which theta becomes larger up to Q₂The suction reference position existing in the range up to this point,

(2) in the step 3, when R 'cos α'/a + R 'sin α'/b < 1, Q is selected in order₁From a clockwise direction in which theta becomes smaller to Q₂A suction reference position existing within the range of up to.

7. The method of manufacturing a three-dimensional shaped object according to any one of claims 1 to 6,

in the suction unit, the respective switching valves corresponding to the respective suction areas, which are not arranged in a state of being continuous without distinguishing the respective suction areas, are provided in a state of being adjacent to the inlets of the respective suction areas, and the switching valve of the suction area that executes the operation command of suction is opened.

8. The method of manufacturing a three-dimensional shaped object according to any one of claims 1 to 6,

in the suction unit, the switching valves corresponding to the respective suction areas, which are disposed in a state of being separated from each other, are provided at the inlet of the suction area or at the middle part of the respective pipes connecting the respective suction areas and the flue gas collector or at the end part on the side of the flue gas collector, and the switching valve of the suction reference position for executing the operation command of suction is opened.

9. The method of manufacturing a three-dimensional shaped object according to any one of claims 1 to 6,

in the suction unit, a suction fan and a suction switch connected to the suction fan are provided in each suction area so as to distinguish the suction areas from each other, and the suction switch and the suction fan in the suction area that execute a suction operation command are operated.

10. The method of manufacturing a three-dimensional shaped object according to any one of claims 1 to 9,

the larger the irradiation amount of the laser beam or the electron beam, the larger the suction amount per unit area of the suction portion is set.

11. The method of producing a three-dimensional shaped object according to any one of claims 1 to 10,

the end of the moulding table is equidistant from the inlet of the fume suction portion around the whole circumference of the moulding table, with the horizontal direction as reference.

12. The method of manufacturing a three-dimensional shaped object according to any one of claims 1 to 11,

the planar shape of the modeling table along the horizontal direction is square, and the smoke suction part forms the side of the square.

13. The method of manufacturing a three-dimensional shaped object according to any one of claims 1 to 11,

the planar shape of the shaping table in the horizontal direction is a circle, and the smoke suction part is arranged concentrically with respect to the circle.